1. Field of the Invention
This invention generally relates to a multi-plate clutch. More specifically, the present invention relates to a multi-plate clutch with a boss that couples a flywheel and a clutch cover assembly, and that drives a friction connecting plate on the input side.
2. Background Information
A multi-plate clutch is often used in such vehicles as racing cars. Multi-plate clutches generally comprise a flywheel on the engine side, a clutch cover assembly disposed axially apart from the flywheel, and a plurality of input and output members (for example, drive and driven plates) disposed between the flywheel and the pressure plate of the clutch cover assembly. The term "multi-plate clutch" as used herein means a clutch in which more than two output portions are disposed and more than three friction connecting faces are formed by the input member and the output member.
The flywheel and the clutch cover in the multi-plate clutch are typically coupled together by, for example, a cylindrical member. The cylindrical member is disposed on the outer circumferential side of the drive and driven plates. The cylindrical member has a plurality of teeth disposed circumferentially next to one another on the inner circumferential face. The teeth of the cylindrical member extend in an axial direction on the inner circumferential face and engage outer circumferential teeth of the drive plate. This engagement makes the drive plate axially movable and circumferentially unmovable against the cylindrical member. In other words, a torque is transmitted from the flywheel to the drive plate via the cylindrical member.
Some multi-plate clutches have a boss not only used to couple the flywheel and the clutch cover together, but also used to drive a drive plate. The boss is often a column like member extending in an axial direction, with radially extending spaces being formed in between circumferentially adjacent column like members. A connecting portion is formed on the outer circumference of the drive plate. The connecting portion is inserted in the spaces described above and engages the boss such that it is axially movable and circumferentially non-movable.
The above mentioned conventional multi-plate clutch of a boss-driving type has a boss which is formed in a body with a clutch cover or a flywheel. Some bosses have a plurality of columnar portions.
When the number of friction faces of the multi-plate clutch is changed by the user, the length of the clutch in an axial direction need to be adjusted by exchanging the boss. In that case, either a flywheel or a clutch cover assembly of a multi-plate clutch with the conventional structure need to be exchanged. In addition, when a boss is exchanged because of its abrasion, either a flywheel or a clutch cover assembly need to be exchanged together with the boss. When a boss has a plurality of columnar portions, this typically increases the number of parts and makes it difficult to maintain the accuracy on assembling them.
In view of the above, there exists a need for a multi-plate clutch which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.